Cysteine proteases

Abstract

The present invention relates to a novel polypeptide which displays IgG cysteine protease activity, and in vivo and ex vivo uses thereof. Uses of the polypeptide include methods for the prevention or treatment of diseases and conditions mediated by IgG, and methods for the analysis of IgG.

The invention claimed is: 
     
       1. A polypeptide comprising a variant of the sequence of SEQ ID NO: 4 which variant:
 (a) is at least 90% identical to SEQ ID NO: 4; 
 (b) has a cysteine (C) at the position in said variant sequence which corresponds to position 102 of SEQ ID NO: 3; and 
 (c) has, at the positions in said variant sequence which correspond to positions 92, 272, 294, and 296 of SEQ ID NO: 3, a lysine (K), a histidine (H), an aspartic acid (D) and an aspartic acid (D), respectively;
 wherein said variant has IgG cysteine protease activity and produces at least the same quantity of cleavage fragments when cleaving human IgG than IdeZ polypeptide and/or produces a greater quantity of cleavage fragments when cleaving human IgG as IdeS polypeptide; and 
 wherein said variant of the sequence of SEQ ID NO: 4: 
 
 (1) has a positively charged amino acid at the position in said variant which corresponds to position 138 of SEQ ID NO: 3, optionally wherein said positively charged amino acid is arginine (R) or lysine (K); 
 (2) has a positively charged amino acid at the position in said variant which corresponds to position 139 of SEO ID NO: 3, optionally wherein said positively charged amino acid is arginine (R) or lysine (K); and/or 
 (3) has at least one of the following modifications: 
 i. a deletion of the leucine (L) and threonine (T) residues at the positions in said variant which correspond to positions 64 and 65 of SEO ID NO: 3; 
 ii. a threonine (T) in place of the arginine (R) at the position in said variant which corresponds to position 70 of SEO ID NO: 3; 
 iii. a deletion of the tyrosine (Y) at the position in said variant which corresponds to position 71 of SEO ID NO: 3; 
 iv. a glutamine (Q) in place of the asparagine (N) at the position in said variant which corresponds to position 72 of SEO ID NO: 3; 
 v. a glycine (G) in place of the asparagine (N) at the position in said variant which corresponds to position 73 of SEO ID NO: 3; 
 vi. an alanine (A) in place of the glutamic acid (E) at the position in said variant which corresponds to position 67 of SEO ID NO: 3; or 
 vii. an asparagine (N) in place of the glutamine (Q) at the position in said variant which corresponds to position 68 of SEO ID NO: 3. 
 
     
     
       2. A polypeptide according to  claim 1 , which comprises or consists of the sequence of SEQ ID NO: 14, optionally wherein said sequence includes an additional methionine at the N terminus and/or a histidine tag at the C terminus. 
     
     
       3. The polypeptide according to  claim 1 , wherein said polypeptide produces at least 2.0-fold more cleavage fragments as compared to IdeZ or IdeS. 
     
     
       4. A polypeptide according to  claim 1  which is less immunogenic than IdeS polypeptide, wherein the immunogenicity of said polypeptide is no more than 85% of the immunogenicity of IdeS polypeptide when measured in an immunogenicity assay. 
     
     
       5. A polypeptide according to  claim 1 , wherein said variant of the sequence of SEQ ID NO: 4 is at least 95% identical to SEQ ID NO: 4. 
     
     
       6. A polypeptide according to  claim 1 , wherein said variant of the sequence of SEQ ID NO: 4 is at least 95% identical to SEQ ID NO: 14. 
     
     
       7. A polypeptide according to  claim 1 , wherein said polypeptide is less immunogenic than IdeS polypeptide and is no more immunogenic than IdeZ polypeptide or IdeS/Z polypeptide, when measured in the same assay.